ISA Local Resource Bus
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The NVRAM and RTC is accessed through the above three registers.
When accessing a NVRAM/RTC location, follow the following
procedure:
1. Write the low address (A7-A0) of the NVRAM to the
NVRAM/RTC STB0 register,
2. Write the high address (A15-A8) of the NVRAM to the
NVRAM/RTC STB1 register, and
3. Then read or write the NVRAM/RTC Data Port.
Refer to the MK48T59 Data Sheet, listed in
, for additional details and programming information.
Module Configuration and Status Registers
Three registers provide the configuration and status information about the
board. These registers are listed in the following table:
The following sub-sections describe these registers in detail.
CPU Configuration Register
The CPU Configuration Register is an 8-bit register located at ISA I/O
address x0800. This register is defined for the MTX to provide
compatibility with existing firmware and AIX revisions. The Base Module
Status Register should be used to identify the base module type and the
System Configuration Register should be used to obtain information about
the overall system for future releases.
Table 1-16. Module Configuration and Status Registers
PCI I/O Address
Function
0000 0800
CPU Configuration Register
0000 0802
Base Module Feature Register
0000 0803
Base Module Status Register
0000 08C0 - 0000 08C1
Seven-Segment Display Register